The present invention relates to a video edit system used in TV broadcast, more particularly to a non-linear video edit system using a digital data recorder that features random access and nonvolatile.
The videocassette recorder (VCR) has been used as a video edit system for a long time. The VCR uses a magnetic tape of sequential access as a recording medium so that in order to play a scene soon after it has been after recorded, it is necessary to wait for the tape to rewind. This prevents quick response. The sequential access and the slow record and play speeds also prevent the quick edit of the already recorded video.
On the other hand, as video compression and decompression technologies have developed, a non-linear video edit system using a recording medium that features fast and random access, such as a magnetic disk, or hard disk drive, has recently begun to be used.
The non-linear video edit system has an edit function called a time line which provides a cut edit by quickly cutting out and combining arbitrary scenes of the video data that has previously been digitized and stored into the disk from external VCRs or video lines. In this process, the cutting out of scenes does not process copies of the video data, but acquires address information identifying the scenes, that is, the start and end position information that points to the locations of the scenes within the video data on the hard disk drive. In the play of the edit result, the non-linear video edit system refers to the scene ID information for reading the corresponding video data contents from the disk to play it. Such video data of the cut scenes, sequentially aligned on the time line, is called a package. This is a very smart and easy way to carry out a cut edit on the video data that has been previously stored into the disk.
It is, however, necessary to be able to carry out edits rapidly in an application such as a news broadcast, so that there may be a request to create the package by the direct edit from the external VCR. In this case, the editor plays the scenes stored in the cassette loaded into the external VCR and records (digitizes) the video data into the disk so that a package comprising those scenes is created at the same time.
Even the non-linear video edit apparatus can not reduce the time for recording the scene that is to be stored. For example, recording a scene requiring three minutes to play requires three minutes to record. The video being recorded can be confirmed or viewed on a monitor in real time, i.e. while it is being recorded. But even if a portion of interest is found or the operator misses watching a portion of interest on the monitor, the portion concerned cannot be viewed until the scene recording finishes. Of course, it is possible to view this portion by suspending the VCR, but it is then necessary to record the whole scene over again even if the viewing shows no problem. On the contrary, if the portion of interest is not viewed during the recording, but viewed after the recording is complete and a problem is found, the recording must be done again from scratch and accordingly recording time has been wasted. In some applications, such as news editing, there is no time to be lost and wasting of recording time is a serious problem. This problem becomes worse as the scene is longer.
Therefore what is desired is to provide a non-linear video edit system that uses such a random access recorder and allows a recorded video portion to be viewed without awaiting completion of the recording and without interrupting the recording even during the recording from an external VCR.
A non-linear video edit system according to the present invention has a random access recorder for recording video data, read and write means for independently executing the write and the read of the video data into/from the random access recorder, a selector for selecting one from the play outputs of an external sequential access recorder and the random access recorder to provide it to an external monitor, and a control means for controlling the read and write means and the selector. When the edit system carries out an overwriting edit or an insertion edit of a played scene from the external sequential access recorder into a package of a plurality of scenes defined by a play list having data representing the start and end positions of each video scene already stored in the random access recorder in response to a first instruction provided by a user, the control means controls the selector to select the play output of the random access recorder following the play list and said played scene of the sequential access recorder to provide it to the monitor so that the user can view the edit result in real time during the writing, and if the user provides a second instruction during the writing, the control means stops the operation of displaying the edit result in real time without interrupting the writing and again provides the same edit result based on an updated temporary play list reflecting the edit result to the monitor from the random access recorder.
According to the present invention, the user can view the written video portion without awaiting completion of the writing and without interrupting the writing even during writing from the external VCR.
In accordance with another aspect of the present invention, a non-linear video edit system has a nonvolatile random access recorder for storing digitized video data, a writing means for writing the video data into the random access recorder, a reading means operating independently of the writing means, a control means for controlling an external sequential access recorder according to user instruction and controlling the writing means and the reading means, and a selecting means controlled by the control means and for selectively providing the play output of the sequential access recorder or the play output from the reading means of the random access recorder to an external monitor. As the play output of the sequential access recorder is written over or inserted into a video scene already stored in the random access recorder, when the control means receives the designation of the overwritten portion or range or the designation of the insertion point of the insertion and the overwriting or the inserted range of the play output from the sequential access recorder to the video scene so that the writing means writes the play output of the sequential access recorder into the random access recorder, it controls the sequential access recorder to start playing from a position at a predetermined time before the start point of said designated range while it controls the reading means of the random access recorder to start playing from a position at said predetermined time before said designated range or point, and controls the selecting means to select the play output of the reading means. After that, when-the play output of the sequential access recorder reaches the start point of the designated range, the control means controls the writing means to start writing the play output of the sequential access recorder as a new video scene different from the video scene stored in the random access recorder and controls the selecting means to select the play output of the sequential access recorder. Following that, when the play output of the sequential access recorder reaches the end point of the designated range, the control means controls the writing means to stop the writing and the selector to select again the play output of the reading means. After that, when the play output of the sequential access recorder reaches a position at a predetermined time after the end point of the designated range, the reading means stops reading and the control means creates a play list identifying the respective scenes resulting from overwriting or inserting said new video scene to the video scene stored in the random access recorder on the time axis by the start and the end point data of the corresponding video scene in the random access recorder without modifying the data of the video scene stored in the random access recorder. If the control means receives an instruction from the user to confirm or view the edit result before the completion of the writing of the whole designated range of sequential access recorder, it continues writing of the play output of the sequential access recorder, creates a temporary play list reflecting the edit result, restarts reading the random access recorder from the position at said predetermined time before the start point according to the temporary play list and controls the selecting means to select the play output of the reading means.
According to this configuration, the stop timing of the play of the sequential access recorder could be any time as long as it is later than the stop of the writing. Besides, it may have the length of the scene instead of, or in addition to, one of the start and the end positions.
This configuration can also confirm the recorded video portion without awaiting completion of the writing and without interrupting the writing even during writing from the external VCR.
It would be better that the control means controls the writing of the play output of the sequential access recorder to start from a position a predetermined time before the start point of the designated range and finish at a position a predetermined time after the end position. This allows said new video scene to be recorded with margins at the beginning and end of the designated range and avoids the danger of creating a blank scene if the edit point moves.
If the user instructs an overwriting or an inserting edit of a slow play output from the sequential access recorder to the video scene recorded in the random access recorder, the control means has the sequential access recorder play at the normal speed while writing it into the random access recorder, creates said temporary play list regardless of the edit result confirmation instruction, and restarts playing to read the random access recorder from the position at said predetermined time before said start point according to the temporary play list and controls the selecting means to select the play output of the reading means so that the play of the slow scene is conducted at the designated slow speed.
This allows the user to view the edit result in real time as if it were being recorded at the slow speed while the recording is conducted at the normal speed in case of the slow play edit.
In case of playing the random access recorder according to the edit result confirmation instruction, it would be better that the control means allows the user a variable speed play operation. Similarly, in case of playing the random access recorder to provide the slow play output in the overwriting or inserting edit, it would be better that the control means allows the user a variable speed play operation. These allow the user more flexible and quick confirmation. Should the user try to play the portion beyond the currently written portion into the random access recorder, the control means stops the advance of the play until it becomes playable to prevent error operation.